Table of Contents
- 1 How does synchronous motor prevent hunting?
- 2 What is hunting in synchronous machines How is it remedies?
- 3 Which of the following are used in preventing the hunting phenomenon in synchronous generator?
- 4 How does damper winding improve the performance of a synchronous machine?
- 5 What are the effects of hunting in synchronous motor?
- 6 What are the losses in a synchronous machine?
- 7 What are the characteristics of a synchronous generator?
How does synchronous motor prevent hunting?
Reduction of Hunting in Synchronous Motor Use of Damper Winding: It consists of low electrical resistance copper / aluminum brush embedded in slots of pole faces in salient pole machine. Damper winding damps out hunting by producing torque opposite to slip of rotor.
What is hunting in synchronous machines How is it remedies?
The motor responds to a decreasing load torque by a temporary increase in speed and a reduction of the torque angle δ. Thus, the rotor swings and rotates around the synchronous speed. Hence, this process of rotation of the rotor speed equal to or around the synchronous speed is known as Hunting.
What is hunting how hunting is prevented?
Hunting or Phase swinging in a synchronous motor is prevented by making a change in the construction of the rotor. Special bars of conductors are embedded in the field poles of the motor.
Which of the following are used in preventing the hunting phenomenon in synchronous generator?
Damper bars
Which of the following are used in preventing the hunting phenomenon in synchronous generators? Explanation: Damper bars try to maintain synchronism between the rotating magnetic field and the rotor so they help in preventing hunting. It produces surges in the machine.
How does damper winding improve the performance of a synchronous machine?
Damper windings helps the synchronous motor to start on its own (self starting machine) by providing starting torque. By providing damper windings in the rotor of synchronous motor “Hunting of machine”can be suppressed.
What is the limiting factor for the diameter of synchronous machine?
The limiting factor for the diameter of synchronous machine is the peripheral speed. The limiting value of peripheral speed is 175 m/sec for cylindrical rotor machines and 80 m/sec for salient pole machines.
What are the effects of hunting in synchronous motor?
Effects of Hunting in Synchronous Motor 1 It may lead to loss of synchronism. 2 Produces mechanical stresses in the rotor shaft. 3 Increases machine losses and cause temperature rise. 4 Cause greater surges in current and power flow. 5 It increases possibility of resonance.
What are the losses in a synchronous machine?
The losses in a synchronous machine affect its cost, rating, and performance. The efficiency of a synchronous machine is frequently determined by measuring the losses, using techniques that are precisely defined by ANSI, IEEE, and NEMA measurement standards.
What are the mechanical and windage losses of a rotor?
The mechanical or friction and windage losses are due to the friction in the bearings and the energy that is dissipated in turning the rotor through the air inside the machine. The rotational losses can be determined by driving the machine at rated speed with no load or excitation.
What are the characteristics of a synchronous generator?
FIGURE 1: Power flow for a synchronous generator. FIGURE 2: Power flow for a synchronous motor. The losses in the synchronous machine are similar to those of the transformer and other types of rotating machines. Like all electrical machines, synchronous machines have copper, steel, rotational, and stray losses.